1. Field of Invention
The present invention relates to oriented polymer chains, e.g., for use in thermal applications such as heat spreading.
2. Discussion of Related Art
Polymer plastics have been widely used for a variety of applications due to their low manufacturing cost, non-reactive stability, and electrically insulating nature. Polymers can be processed to exhibit strong mechanical properties while still remaining lightweight, for example, making them ideal for packaging and protective use. However, polymers generally exhibit low thermal conductivity, limiting their use in heat distributing or spreading type functions. It would be beneficial for the thermal conductivity of polymer plastics to be tailored, allowing these materials to branch out into an even wider space of industry applications.
The low thermal conductivity properties indicative of most polymers is attributed to two main factors. The first factor is gyration of the polymer chains, which shortens the effective mean free path of thermal lattice vibrations within the polymer. The second factor is the presence of weak inter-chain links, which serve to create thermal boundary resistance between the chains. However, single polymer chains are known to exhibit very high thermal conductivity along the polymer chain direction. For example, polyethylene (PE) fibers have been observed to have a thermal conductivity of about 20 W/mK.